Two people are under arrest after a grandmother was found dead inside a home on Long Island and her 24-year-old grandson slashed.

Police arrested 23-year-old Benjamin Lopez and 19-year-old Deangelo Gill late Wednesday night. They are being charged with second-degree murder.

Officials say the two suspects waited until they knew the grandmother would be alone, with a plan to rob her house of drugs and money and to kill her if she got in the way. Authorities say their actions were an effort to do harm to her 24-year-old grandson, with whom they dealt drugs, after some of the dealings had apparently gone bad.

Police say they watched the house on North Newbridge Road Levittown Wednesday afternoon, and when they saw the grandson leave, they went into the house and attacked.

The suspects allegedly beat 73-year-old Laraine Pizzichemi in her bedroom and stabbed her, then began to rob the house. After that, the grandson came home, and they attacked him with a large knife, police said. During the course of the incident, he was secretly able to call 911.

At some point, a 21-year-old woman arrived at the house and also called 911. She was not harmed.

"This poor woman didn't have a chance to defend herself," acting Nassau County Police Commissioner Patrick Ryder said. "She didn't have a chance to say anything. She was attacked in her home by these two individuals and brutally assaulted."

Police say when they arrived at the home, the suspects were still inside. They fled out the back door and jumped fences to escape, with officers pursuing them. They reportedly ran right to Lopez's house just a few blocks away, where police promptly took them into custody.

Officers recovered a handgun, several cutting instruments and a large knife at the murder scene.